Method of carrying out electrothermic reactions



July 18, 1944. c. e. sun's METHOD OF CARRYING OUT ELECTROTHERMICREAGTIONS Fiied Feb. 26, 1941 2 Sheets-Sheet 1 Fig.1.

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Chauncey G. Suits,

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His Attorney y 1944- c. G. sun's METHOD OF CARRYING OUT ELECTROTHERMICREACTIbNS Filed Feb. 26, 1941 Chaunc by/I Il'l Patented July 18, 1944METHOD OF CARRYING OUT ELECTRO- THEBMIC REACTIONS Chauncey. G. Suits,Schenectady, N. Y., assignor to General Electric Company, a corporationof New York Application February 26, 1941, Serial No. 380,640

9 Claims. (Cl. 204 -171) The present application is acontinuation-inpart of my prior application, Serial No. 275,203, filedMay 23, 1939.

The present invention relates to the production of transient electricarcs which are suitable for the generation of gases, and in particularhydrocarbon gases such, for example, as acetylene. The method featuresof my invention will be pointed out with particularity in the appendedclaims. Apparatus features of my invention are claimed in a copendingapplication Serial No. 479,348, filed March 16, 1943.

I have discovered that when an electric current of properly chosenvoltage and amperage is conducted through a bed or column of contactingparticles or pellets of conducting material, such as carbon for example,immersed in mineral oil, or other carbo-hydrogen compound of poorconductivity, the formation of transient electric arcs takes placebetween the particles because of their separation due to gas formationat the contacts of relatively high transition resistance betweencontacting particles. The electric arcs are of momentary duration, andare accompanied by the evolution of gas. The individual arcs appear tobeterminated by the evolution of gas, which disturbs the position ofarcing particles with respect to neighboring particles. Under conditionsto be set forth, the evolved gas consists preponderantly of hydrogen andacetylene. My invention, therefore, in one of its aspects includes aprocess of generating acetylene and other gases.

Referring to the drawings, the apparatus illustrated by Fig.1 includes,in addition to the essential features of an apparatus for carrying outmy invention, also various automatic auxiliary devices and variousnon-essential structural details.

The gas-generating apparatus comprises an arc chamber I, which isprovided with cooperating electrodes 2 and 3 which are spaced apart andrespectively makecontact with a bed or stratum of discrete particles ofconductive material 4, the particles being arranged movably incontacting relation. During operation transient arcs are formed atpoints of contact between adjacent particles. The material 4 preferablyconsists of loose lumps or particles of carbonaceous material such, forexample, as coke, coal, amorphous carbon or graphite. The carbonaceousparticles may have a diameter ranging from about 1 inch up to one inch,the preferred size being about onequarter inch. Although comminutedcarbonaceous material is preferred as the material 4, the employment ofcarbides, metals, or other conductive material is not excluded.

As the relatively non-conducting liquid I may employ a liquidhydrocarbon such as mineral oil or benzol. An oil of vegetable orbiologic origin, as for example turpentine, oleic acid, or mixtures suchas a solution of sugar in water also may be used. Such various organicmaterials, for the present purpose, will be termed genericallycarbohydrogen compounds. The liquid fills the spaces between theparticles in the bed of comminuted material between the electrodes. Theliquid conveniently is introduced through ducts 5 extending through thelower electrode 2 as indicated. The distance between the electrodes 2, 3is not critical. This spacing ordinarily should be at least about oneinch, and may be up to many inches in length.

Although the structure of the conversion chamher and electrodes may bevaried, depending on the reaction to be carried out, the nature of thereacting ingredients, and other factors, it may be said for illustrativepurposes that the container I may consist of suitable metal, such asiron, and may be provided with a lining which in the apparatusillustrated consists of two layers, a layer 6 of non-conducting materialsuch as heat-hardened phenolic resin or the like, and layer 1 of alundumwhich is adjacent to the arcing zone. The electrodes 2, 3 may consist ofgraphite. The electrode 3 is attached to a stem 9 consisting of copperor other suitable conductive material which is surrounded by a sheathll! of alundum, or other suitable refractory insulating material. Theelectrode stem 9 is insulated from the container by a bushing II ofsuitable insulating material as, for example, a phenolic resincomposition.

The non-conducting liquid is introduced by a conduit l2 whichcommunicates with the ducts 5 and leaves the reaction chamber through astrainer l3. The liquid material then is conveyed through a conduit 14by a pump I5 into a settling tank Hi from whence it is returned by theconduit 12 to the reaction chamber. In the tank I6, fine particles, suchas carbon black, which may be formed in the liquid are largely removedby the strainer I'I. Additional amounts of oil may be introduced througha conduit. I8 containing a one-way valve 44, as will be later described.

Assuming the space between the electrodes to contain carbon granules andthe space between the granules to be filled With a suitable liquid, suchas mineral oil, in which the particles move freely due to theirbuoyancy, a current of at least about an ampere at suitable potential ofat least 30 volts is supplied to the electrodes by the range fromseveral hundred to one thousand volts may be employed for an electrodeseparation of one inch.

ed to the reaction chamber by conduits 33, 36. If the liquid falls belowa predetermined level then, by the operation of automatic mechanism.

Vigorous arcing occurs due to gas generation at the points of contact ofadjacent granules and the consequent separation thereof, each are beingaccompanied by the generation of gas and in turn being extinguished bythe gas evolution. No ballast or series steadying resistance in the arccircuit is required. The duration of the transient arcs ranges fromabout .00006 second to .01 second, the arcs of relatively long durationin this range being more common.

Under the conditions above described, that is, when particles or lumpsof carbonaceous material, such as coke, about one-quarter inch in size,are introduced in loose contact between graphite electrodes spaced apartabout oneinch, and when a body of mineral oil or the lik envelops suchparticles or lumps, then with an applied voltage of about 500 volts anda mean current of about 50 to 100 amperes the results obtained 'by thepractice of my invention in general are as follows:

Vigorous evolution of gas results from the transient arc discharges,which being of short duration no-general heating of the carbon particlesoccurs. Since the carbon particles are surrounded by a continuous liquidbath, the temperature of the coke may not, and ordinarily does not,appreciably exceed that of the liquid. The reaction chamber, which, asillustrated, is large relative to the mass of liquid acted upon, alsofunctions as a heat-dissipating means. The solid conducting particles donot reach oil-cracking temperatures except perhaps at minute local areaswhich are highly heated only temporarily by arcs terminating thereon.Although th oil becomes heated in the zones of the transient arcsbetween the carbon particles, it does not become heated as 'a Wholesufficiently to be cracked or destructively decomposed thermally, thatis, other than by the action of the arcs. For example, the body ofmineral oil may assume, outside of the arcing zones during the operationof the process, a temperature within the range'of about 250 toadditional liquid is introduced. The float v35 which is linked to aswitch 36, closes the enep gizing circuit 31, 38 of a motor 39 which ismechanically connected to a pump 40 supplying oil to the oil inlet l8.By the rotation of the pump I5 connected to a motor 39', circulationofthe liquid between the reaction chamber and the tank 16 is provided.The switch 36 has been conventionally indicated to represent anysuitable form of switch, such for example as a mercury switch 300 C.,which is well'below a temperature of thermal decomposition.

The gas which is generated in the arc passes through the oil and isdrawn off by a conduit 22.

The gas consists of approximately three parts of hydrogen to two ofacetylene, together with small admixtures of other hydrocarbons.

During the operation of the arcs, consumption of carbon occurs and asthe level of the carbon granules falls, decreased conductivity resultsIce-- tween the electrodes 2 and 3. man automatic apparatus, thereduction of the current'in the conductor 21 weakens its effect on thesolenoid of the relay 23 until its armature 24 bridges the contacts inthe circuit 25, 26 of the motor 21. The motor is connectedby the gears28 to a feed screw 29 located in a supply chamber 30. Due to theoperation of the feed screw 29, additional -limit, then the contacts ofthe relay 6| of the form described in United States Letters Patent No.2,101,092. A one-way valve 44 is provided to hold pressure in the tankI6 when required. The energizing circuit 31, 38 has not been shown inits entirety and the source of current has been omitted to avoidcomplicating the drawing.

The gaseous pressure in the reaction chamber also may be automaticallycontrolled by a relay ll one contact element of which is connected to asylphon bellows 42. For example, if the pressure of the gas should riseabove a predetermined are opened, thereby energizing a circuit breaker43 which open-circuits the power supply lines 20, 2|.

In the apparatus shown in Fig. 2, one of the electrodes is rotatedtransversely with respect to its cooperating electrode and thereby isrendered capable of agitating the particles of cok or other conductingmaterial. This apparatus, like the apparatus of Fig. 1, comprises acontainer 45 provided with a suitable lining 46. At the base of thischamber is a stationary carbonaceous electrode 41, for example, anelectrode of graphite, to whichis connected an electric terminal 48 by abolt 49. The are chamber is closed by a cover 50 consisting of suitableinsulatingmaterial such asan asbestos composition which is bonded withfastened down upon the container wall by the threaded bolts 51which-engage with nuts 52. Passing through the cover is an insulatingsleeve 53 which may consist of the same asbestos composition. It ispressed upon a shoulder of the cover aperture by a ring 54, a suitablepacking being provided as indicated. The external threads of the ring 54engage. with the internal threads of a ring 55 which is bolted to thecover 50. Within the sleeve 53 is held a metal sleeve 56 within whichturns a shaft 51, the lower end of which carries a conical bearingmember 58. The latter is urged into seating relation to another bearingmember 59 by a spring 60 at the upper end of the shaft 51. This springis held under compression between a shoulder 6| on the shaft and aninsert 62 in the top of the sleeve 56. The lower end of the rotatable.shaft 51 carries an offset electrode 63 which is held eccentrically by apin 64 on a link plate 65. The electrode 63 is urged upwardly againstthe plate 65 by a spring 66 which is held under compres-.

sion in a recess as shown between a shoulder 61 321d a pressure plate 68bearing'on the electrode The electrode shaft 51 is arranged to berotated by a gear 10 engaging with a driving member 1|. Electric energyis supplied by a stationary brush contact 12 bearing against a rotatingring contact 13. The eccentrically mounted electrode 64 when rotatedexerts a stirring effect on a mass 15 of carbon granules which areimmersed in a charge 16 of hydrocarbon oil, or the like, in the arcchamber. The gaseous products produced by arcing escape from thereaction chamber'through a flue ll. The rotatable electrode and attachedparts are arranged to be lifted by engagement with a ring ll.

Initially stirring of the charge is not required as with oil of ordinaryviscosity, the coke particles remain localized in the bottom oi. theconversion chamber between the electrodes and normal arcing as abovedescribed occurs therein. As arcing proceeds and oil decompositionproceeds with the formation of gaseous products, the residue becomesthickened, largely due to accumulation of "carbon black. s When aboutone-half of the oil volume has been converted to gas the viscosity ofthe remaining volume of. oil becomes suiilciently increased to cause thecoke to become dispersed throughout the body of. thickened oil, therebydecreasing the mobility of the conducting particles so that satisiactoryarcing no longer occurs. If it is attempted 'to increase the rate ofarcing by introducing additional charge of coke particles, the conditionof I v so high that no arcing whatever would take place with astationary electrode, a satisfactory rate of arcing and oil conversionmay be maintained with an electrodespeed of one revolution in threeseconds. A When employing mineral oil or other hydrocarbonaceous liquidas the quenching, agent in the arc chamber, the gases evolved consist ofa mixture of hydrogen, acetylene, and small amountsot otherhydrocarbons. Th percentage oi. acetylene varies from about 30 to 40 percent by volume, depending on the operating conditions. In generaLtheeiiiciency oi the apparatus increases with the size of the arc chamberwith increase of impressed voltage and with increase in temperature ofthe mineral oil or other quenching liquid.

Th efllciency oi acetylene production is about .009 kilowatt hour perliter (.255 kilowatt hour per cubic foot), although even higherefliciencies have been obtained under carefully controlled conditions.

It is desirable, in order to obtain maximum efliciency of gasproduction, to so operate the ap- (paratus that the ordinary conductingcurrent between the electrodes should be kept at a minimum, the arccurrent then being at a maximum. The are current is evidenced on theoscillograph by a succession of high, narrow peaks in the current. Whenusing ordinary alternating current, the absence oi arcing componentwould be evidenced by the current through the apparatus having the usualsmooth sine wave form. When arcing occurs, sharp peaks are superimposedon the sine wave which progressively becomes reduced relatively until atmaximum arcing the sine wave becomes replaced by narrow, high peaks ofcurrent. a

Apparently the evolution 01 gas at the points oi arc formation forcesthe arcing contacts between theloose particles apart until the arcs areextinguished and the gases are suddenly cooled.

\ assavvo 3 n The reaction 2C+Ha=CiHz, which normally would tend to beestablished in a liquid hydrocarbon in high temperature equilibrium,thus is forced to the right, resulting in the evolution of acetylene.While I do notwish to be limited by any theory of operation, I believethat the production of acetylene is conditioned by numerous transientarcs formed between the loose particles of conducting-material creatingnumerous localized reaction zones which are heatedto high temperaturesfor intervals of extremely short duration, and is chemically stabilizedby being subsequently cooled at a high rate upon cessation of arcing ineach local reaction zone.

The gas mixture may be separated and puri- What I claim as new anddesire to secure by n 7 Letters Patent of the United States is:

1. The method of generating hydrocarbon gas which consists in immersinga column of movably contacting particles of carbonaceous material in abody of a liquid comprising a hydrocarbon compound, conducting anarc-supporting current of at least about an ampere at a potential of atleast about volts through said column thereby forming a plurality oftransient electric arcs at points of contact of said particles, saidarcs being accompanied by decomposition 30 of said hydrocarbon compoundin the vicinity of said arcs thereby producing hydrocarbon gas, andmaintaining said liquid otherwise below decomposition temperature.

2. The method of generating acetylene which consists in conducting anarc-supporting electric current of at least about an ampere at a po-- Ytential of several hundred volts through a bed of carbon particlesranging from one-sixteenth to about an inch in diameter, immersed in abody 40 of mineral oil whereby a succession of transient arc-likedischarges is caused to occur between said particles accompanied by theevolution or gas including acetylene, and maintaining said body of oilas a whole at a temperature of about 5 250 to 300 C.

3. The method of producing acetylene which" consists in submergingpellets of an electrically conducting solid in an electricallynon-conduct ing liquid carbo-hydrogen compound in electric contact withone another while being free to move, passing through said particles anelectric current of such voltage and amperage that vigorous arcingoccurs between adjacent particles, the

arcs having a duration ranging from about .00006 to .01 second,maintaining said liquid compound below decomposition temperature, andconducting away gas which is evolved by the eiiect of said arcing onsaid carbo-hydrogen compound.

4. The method of producing acetylene which 80 consists in submergingloose particles. of carbonaceous material in a liquid hydrocarbon,arranging said particles in an electric circuit in contact with oneanother submerged in said hydrocarbon while being tree to move, passingthrough said circuit an electric current of such voltage and amperagethat electric arcs having a duration ranging from about .00006 to .01second are formed between such particles accompanied by the evolution ofgases including acetylwe and collecting said gases.

tactsoi high transition resistance with one anither in a bedrsaidparticles being sufllciently iisplaceable to permit separation thereofby the formation of, gas therebetween, establishing an electric circuitthrough said bed, Supplying a cur rent of such voltage and amperage tosaid circuit that-electric arcs may be formed having sufflcient energytocause decomposition oi said liquid hydrocarbon, the evolution of gasbetween adjacent particles causing alternate separation andcontactthereof and thereby'the formation, extinction and reformation ofintermittent electric arcs therebetween, and maintaining said liquidhydrocarbon exterior to the environment of said" perature not materiallyexceeding 300 C. whereby resulting gases are cooled and stabilized.

'7. The method of producing ,hydrocarbon gas from a liquid comprising acompound containing combined hydrogen and carbon which consists inconducting an arc-supporting electric current between particles ofcarbonaceou material which are in contact with ofie another whileimmersed in said liquid and buoyed thereby with freedom of motion,thereby causing gas generation at points of contact, resulting inseparation of said particles andthe formation or transient arcs betweensaid particles in said liquid whereby gas is generated, maintaining saidliquid outside of the regions of contact, with said arcs at atemperature 'of substantial stability and carrying away the gasgenerated by said arcs.

8. The method of producing gas including acetylene from ahydrocarbonaceous liquid which consists in conducting electric current,the value or which is at leastas high as one ampere between pellets ofcarbonaceous material which are in electrical contact with one anotherwhile said pellets are immersed in said liquid thereby causingsuflicient generation of gas-to result in separation of said pelletsaccompanied by are formation whereby gas is generated, mechanicallyagitating said liquid to increase the mobility of said particles,maintaining said liquid outside 01' the environment of such arcs intactfrom thermal decomposition and collecting the gas thus formed.

9. The method of producing gaseous products including acetylene frommineral oil which consists in conducting betweencarbon particlesalternating current ofat least about one ampere. about cycle frequencyand having a potential within a rangeof about'30 to several hundred,

volts, said particles being immersed in said oil while held in contactwith one another and being buoyed by said oil with sufllcient freedom ofmotionto cause such conduction of current to result in transient arcingbetween contacting carbon particles accompanied by the generation of thegaseous products, maintaining said oil as a.

whole at a temperature not materially higher than about 300 ;U.', .andcarrying away the desired gaseous products.

CHAUNCEY G. SUITS

